Sed: would like to return an error for empty string
There are actually two things that I want to do:
1. Detect if there is a 3 digit number and if so return an error (working)
2. Detect if there is an empty string and return an error if so (not working)
I would like to do 1 & 2 using the sed command only once; I'm trying to do things correctly and efficiently.
I have so far:
(For newbies: -n quiets text output, -r allows for GNU program to do true regex, {q100} returns error '100', '$?' is the last returned result)
The result is 0, which is not what I want as the string is empty. My attempt is the portion '//{q100}', but I can see that it is difficult to test against nothing-quite perplexing actually.
Hi,
I need to check for value not equal (<>) to 21 and not equal empty or null values.
Please modify this script
if
then
echo "$VALUE,$BSC_NAME,$BSC_ID" > $OUT_FILE/power_up.out
end if
TQ (5 Replies)
Hello All,
I have written shell script whcih at the max 3 parameters.
When only one commandline argument and other two command line arguments are passed as empty string like
eg : archive ' ' ' '
Then i need to check whether the commandline... (12 Replies)
Hi All,
I am new to unix worldd .
I need to check a file1 if its empty or not.
If its empty then return a non zero value say 99
could you pls let me know the perl script for this. (2 Replies)
Hi one to All
i have written the code for searching the string in the file for specified path. its working fine,
but my req:if the string is not available in the file , it should display the Message saying that , string is not available in the file.
code is:
echo "give the path where... (12 Replies)
hi,
when i am doing the following things getting error
Can anyone please suggest
i have a file where there is a line like the following
branch=dev sdf dev jin kilii fin kale boyle dev james dev
i want to search the existance of dev in the above line.
cat "$file" | sed -n... (8 Replies)
here is what i want to achieve... consider a file contains below contents. the file size is large about 60mb
cat dump.sql
INSERT INTO `table1` (`id`, `action`, `date`, `descrip`, `lastModified`) VALUES (1,'Change','2011-05-05 00:00:00','Account Updated','2012-02-10... (10 Replies)
I am reading from a file and executing the jobs with/without parameters as the job requires.
File
job1 R
job2
job3 Y 123
if
then
<job>.ksh
else
<job>.ksh $params
fi
This works fine if the line read from the file has parameters
it executes like job1.ksh R
But for... (2 Replies)
Hi,
I have a shell script where I am trying to unzip bunch of files zip files one by one. But out of many zip files, if any one zip file is empty, the unzip command sends a non-zero return code and fails the script.
I am trying to see if I can get a success error code even if the script... (2 Replies)
Hello
So i have that script collection, in which i have a single script to create a configuration file.
In there, i have multiple occourences of something like this:
prj_title=$(tui-read "What is the TITLE? ($prj_name):")
] && prj_title="${prj_name/_/ }"
They all work as expected, if... (5 Replies)
Discussion started by: sea
5 Replies
LEARN ABOUT PHP
empty
EMPTY(3) 1 EMPTY(3)empty - Determine whether a variable is emptySYNOPSIS
bool empty (mixed $var)
DESCRIPTION
Determine whether a variable is considered to be empty. A variable is considered empty if it does not exist or if its value equals FALSE.
empty(3) does not generate a warning if the variable does not exist.
PARAMETERS
o $var
- Variable to be checked
Note
Prior to PHP 5.5, empty(3) only supports variables; anything else will result in a parse error. In other words, the follow-
ing will not work: empty(trim($name)). Instead, use trim($name) == false.
No warning is generated if the variable does not exist. That means empty(3) is essentially the concise equivalent to !isset($var)
|| $var == false.
RETURN VALUES
Returns FALSE if $var exists and has a non-empty, non-zero value. Otherwise returns TRUE.
The following things are considered to be empty:
o "" (an empty string)
o 0 (0 as an integer)
o 0.0 (0 as a float)
o "0" (0 as a string)
o NULL
o FALSE
o array() (an empty array)
o $var; (a variable declared, but without a value)
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 5.5.0 | |
| | |
| | empty(3) now supports expressions, rather than |
| | only variables. |
| | |
| 5.4.0 | |
| | |
| | Checking non-numeric offsets of strings returns |
| | TRUE. |
| | |
+--------+---------------------------------------------------+
EXAMPLES
Example #1
A simple empty(3) / isset(3) comparison.
<?php
$var = 0;
// Evaluates to true because $var is empty
if (empty($var)) {
echo '$var is either 0, empty, or not set at all';
}
// Evaluates as true because $var is set
if (isset($var)) {
echo '$var is set even though it is empty';
}
?>
Example #2
empty(3) on String Offsets
PHP 5.4 changes how empty(3) behaves when passed string offsets.
<?php
$expected_array_got_string = 'somestring';
var_dump(empty($expected_array_got_string['some_key']));
var_dump(empty($expected_array_got_string[0]));
var_dump(empty($expected_array_got_string['0']));
var_dump(empty($expected_array_got_string[0.5]));
var_dump(empty($expected_array_got_string['0.5']));
var_dump(empty($expected_array_got_string['0 Mostel']));
?>
Output of the above example in PHP 5.3:
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
Output of the above example in PHP 5.4:
bool(true)
bool(false)
bool(false)
bool(false)
bool(true)
bool(true)
NOTES
Note
Because this is a language construct and not a function, it cannot be called using variable functions.
Note
When using empty(3) on inaccessible object properties, the __isset() overloading method will be called, if declared.
SEE ALSO isset(3), __isset(), unset(3), array_key_exists(3), count(3), strlen(3), The type comparison tables.
PHP Documentation Group EMPTY(3)